1. Field of the Invention
The present invention relates to a wafer cleaning device, a wafer cleaning method and a chemical mechanical polishing (CMP) machine using them respectively suitable for using for cleaning processing after flattening in a CMP machine for example.
2. Description of the Related Art
In a wafer processing process when system LSI is manufactured, the irregularities of an interlayer between wires are flattened using chemical abrasive by a CMP machine. Particles and chemical abrasive that adhere to the flattened wafer are removed by cleaning by a wafer cleaning device. Heretofore, a wafer cleaning device provided with a roll brush is known. In this type of wafer cleaning device, as shown in FIG. 9, cleaning is performed by rolling a roll brush 1 made of soft material such as polyurethane and touching its rolled contact surface to the cleaned surface 3 of a wafer W. As for the roll brush 1, one end in the direction of an axis is supported by a supporting section 5 so that the roll brush can be rolled around the axis freely as shown in FIG. 10. In the above conventional type example, a driven roll 7 which can be rolled freely is arranged on the reverse side (on the lower side shown in FIG. 10) of the roll brush 1 with the wafer W in the center. Therefore, the wafer W is held by the roll brush 1 and the drive roll 7 and the cleaned surface 3 is cleaned, being pressed by the rolled roll brush 1.
Heretofore, plural wafer cleaning devices provided with the same structure are provided in a cleaning processing process and each wafer after flattening processing is distributed in the plural wafer cleaning devices and parallel processing is performed.
However, as a result of measuring particles on a wafer cleaned by a wafer cleaning device, it becomes clear that the above plural wafer cleaning devices are different in wafer cleaning ability though they have the same structure. As a result of examining a factor of the difference made among the devices, it becomes clear that the above difference is related to parallelism shown in FIG. 11 between the wafer W and the roll brush 1.
However, in the conventional type wafer cleaning device, for parallelism between the wafer and the roll brush, a criterion is not particularly provided. Therefore, the above parallelism is determined when the device is assembled, depends upon the precision of a part and the precision of assembly and is actually not controlled.
As a mechanism for adjusting parallelism between the wafer and the roll brush is not provided, parallelism is required to be adjusted by inserting a shim (a spacer for adjusting clearance) between parts and others in case the parts are to be kept in parallel, complicated skilled technique is required and quantitative adjustment is disabled.
Further, there is a problem that even if parallelism is set to an optimum value, it is difficult to continue to kept the parallelism and as means for detecting the change of the parallelism is not provided, the current parallelism is not guaranteed.
The present invention is made in view of the above situation and the object is to provide a wafer cleaning device and others wherein quantitative parallelism can be simply and promptly acquired and in addition, the change of parallelism can be grasped.
A wafer cleaning device according to the present invention to achieve the above object is based upon a wafer cleaning device provided with a roll brush one end in an axial direction of which is supported so that the above roll brush can be rolled around the axis freely wherein cleaning is performed by touching the rolled contact surface of the rolled roll brush to the cleaned surface of a wafer and is characterized in that one end of a roll brush is supported so that the roll brush can be displaced by adjustment means to enable its axis to be tilted to the cleaned surface of a wafer. Also, one end of a rollable driven roll arranged on the reverse side of the above roll brush may be also supported by the adjustment means so that the roll brush can be displaced to enable its axis to be tilted to the cleaned surface of a wafer and each one end of the roll brush and the driven roll may be also supported so that the roll brush can be displaced by the adjustment means to enable each axis of both to be tilted to the cleaned surface of the wafer. Hereby, minute adjustment the degree of freedom of which is high is also enabled.
In the above wafer cleaning device, a position in which one end of the roll brush is supported is displaced and the axis of the roll brush is tilted to the cleaned surface of a wafer by rolling and adjusting a dial adjusting screw which is the above adjustment means manually. Hereby, positional adjustment between the cleaned surface and the roll brush is quantitatively enabled without requiring skilled technique.
The above wafer cleaning device is also characterized in that displacement detecting means for detecting the change of distance between the cleaned surface of a wafer and the roll brush is provided. Control means for feeding back the result of detection by the above displacement detecting means and automatically adjusting the above adjustment means may be also provided. Hereby, cleaning can be promptly performed at precise parallelism.
According to the wafer cleaning device, the change of distance between the cleaned surface and the roll brush is grasped by the displacement detecting means and cleaning by the roll brush in a state in which parallelism is deteriorated can be prevented beforehand. Hereby, the adhesion of particles and slurry to a wafer is prevented from being increased by cleaning by the roll brush the parallelism of which is deteriorated.
The wafer cleaning device is also characterized in that parallelism between the facing surface parallel to the axis of the above rolled contact surface and the cleaned surface of a wafer is set to 0.1 mm or less.
In the wafer cleaning device, the deterioration of the cleaning ability of the roll brush which becomes remarkable in case the parallelism is more than 0.1 mm is prevented and particles and slurry are removed by the very high cleaning ability of the roll brush (the above numerical value is the case of a wafer 8 inches (20 cm) in diameter, however, it hardly need be said that optimum parallelism also increases as the number of the inch of a wafer increases).
The present invention also discloses a method of cleaning a wafer to achieve the above object. That is, a method of cleaning a wafer according to the present invention is characterized in that one end of the roll brush is supported so that the roll brush can be displaced by adjustment means to enable the above axis to be tilted to the cleaned surface of a wafer in a process for touching the rolled contact surface of the roll brush one end in an axial direction of which is supported so that the roll brush can be rolled around the axis freely to the cleaned surface of a wafer and a method of cleaning a wafer by rolling the roll brush.
In the wafer cleaning method, a position in which one end of the roll brush is supported is displaced and the axis of the roll brush is tilted to the cleaned surface of a wafer by rolling and adjusting a dial adjusting screw which is the above adjustment means manually. Hereby, the adjustment of quantitative position between the cleaned surface and the roll brush is enabled without requiring skilled technique.
The wafer cleaning method is also characterized in that a displacement detecting process for detecting the change of distance between the cleaned surface of a wafer and the roll brush is provided. A control process for feeding back the result of detection in the displacement detecting process and automatically adjusting the above adjustment means may be also provided. Hereby, cleaning can be promptly performed at precise parallelism.
In the wafer cleaning method, the change of distance between the cleaned surface and the roll brush is grasped in the displacement detecting process and cleaning by the roll brush in a state in which parallelism is deteriorated can be prevented beforehand. Hereby, the adhesion of particles and slurry to a wafer is prevented from being increased by cleaning by the roll brush the parallelism of which is deteriorated.
The wafer cleaning method is also characterized in that parallelism between the facing surface parallel to the axis of the rolled contact surface and the cleaned surface of a wafer is set to 0.1 mm or less.
In the wafer cleaning method, the deterioration of the cleaning ability of the roll brush which becomes remarkable when parallelism is larger than 0.1 mm is prevented and particles and slurry are removed by the always high cleaning ability of the roll brush (the above numerical value is the case of a wafer 8 inches (20 cm) in diameter, however, it hardly need be said that optimum parallelism also increases as the number of the inch of a wafer increases).
To achieve the above object, the present invention also discloses a chemical mechanical polishing machine. That is, the chemical mechanical polishing machine according to the present invention is characterized in that it is provided with a polishing module and a cleaning module, the cleaning module is provided with a roll brush one end in an axial direction of which is supported so that the roll brush can be rolled around the axis freely, cleaning is performed by touching the rolled contact surface-of the rolled roll brush to the cleaned surface of a wafer and one end of the roll brush is supported so that the roll brush can be displaced by roll brush adjustment means to enable the axis to be tilted to the cleaned surface of a wafer. One end of a rollable driven roll arranged on the reverse side of the roll brush may be also supported so that the roll brush can be displaced by the adjustment means to enable the axis to be tilted to the cleaned surface of a wafer and each one end of both of the roll brush and the driven roll may be also supported so that the roll brush can be displaced by the driven roll adjustment means to enable the axis to be tilted to the cleaned surface of a wafer. Hereby, minute adjustment is also enabled.
Also, in the chemical mechanical polishing machine, a position in which one end of the roll brush is supported is displaced by rolling and adjusting a dial adjusting screw which is the above adjustment means manually and the axis of the roll brush is tilted to the cleaned surface of a wafer. Hereby, positional adjustment between the cleaned surface and the roll brush can be quantitatively made without requiring skilled technique.
The chemical mechanical polishing machine is also characterized in that displacement detecting means for detecting the change of distance between the cleaned surface of a wafer and the roll brush is provided. Further, control means for feeding back the result of detection by the displacement detecting means and automatically adjusting the adjustment means may be also provided. Hereby, cleaning can be promptly performed at precise parallelism.
In the chemical mechanical polishing machine, the change of distance between the cleaned surface and the roll brush is grasped by the displacement detecting means and cleaning by the roll brush in a state in which parallelism is deteriorated can be prevented beforehand. Hereby, the adhesion of particles and slurry to a wafer is prevented from being increased by cleaning by the roll brush the parallelism of which is deteriorated.
The chemical mechanical polishing machine is also characterized in that parallelism between the facing surface parallel to the axis of the rolled contact surface and the cleaned surface of a wafer is set to 0.1 mm or less.
In the chemical mechanical polishing machine, the deterioration of the cleaning ability of the roll brush which becomes remarkable when parallelism is larger than 0.1 mm is prevented and particles and slurry are removed by the always high cleaning ability of the roll brush (the above numerical value is the case of a wafer 8 inches (20 cm) in diameter, however, it hardly need be said that optimum parallelism also increases as the number of the inch of a wafer increases).